1. Field of the Invention
The present invention relates to an apparatus and method for controlling the power quality applicable to a power conditioning system, such as a solar power generation system, or the like, and more particularly, to an apparatus and method for controlling the power quality of a power generation system capable of compensating for harmonic distortions due to non-linear loads and improving power quality accordingly, by performing an active power filter function regardless of whether or not the power generation system performs power generation.
2. Description of the Related Art
Generally, electronic products such as computers, communications devices, medical devices, military devices, or the like, have loads sensitive to power quality. Since these industrial, commercial and military loads are operated by being connected to each other during an automatic process, a power generation system connected to these loads has been very sensitive to power quality PQ.
Generally, as products having non-linear load characteristics may have a bad effect on the power quality of the power generation system, there are products having adjustable speed drive (ASD), switching mode power supply, arc furnace, or the like, mounted therein.
Meanwhile, power quality is classified into voltage quality and current quality. First, in the case of voltage quality, factors, such as instantaneous voltage sags/swells, under/over voltage, interruptions, noise, and other factors such as DC offset, harmonics, interharmonics, notching, or the like, voltage imbalance, voltage fluctuation/flicker, or the like, are handled. These factors, degrading the voltage quality, may be causes of malfunctions or defaults within electrical and electronic devices. When these states occur, dielectric breakdown, device loss, the deletion of memory data of a controller, changes in lighting brightness, shutdowns or resetting of devices, overheating of motors, transformers, and wiring, or the like, may be caused in various facilities.
Next, as the current quality, a default of a power supply, such as voltage distortion in response to current distortion caused due to the increase in the non-linear load, or the like, is handled.
Meanwhile, the power generation system according to the related art cannot compensate for the distortions caused at the time of connecting the non-linear loads and may cause a trip accident or a malfunction in sensitive loads by generating a voltage drop in a pulse type due to the flowing of a pulse-type current into an AC power generation system and line impedance of a power division network, when the non-linear loads are connected.
Therefore, there are problems in that a distribution current transformer causes an increase in operation loss to overheat the transformer and shorten the lifespan thereof and is broken due to resonance between adjacent distribution systems occurring in 5-order and 7-order voltage harmonics.